Synthesis, crystal structures and properties of three rare earth substituted germanotungstates: M/[α-GeW11O39] (M = Nd, Eu, and Tb)

Three new polyoxometalate compounds based on the lacunary Keggin anion [α-GeW11O39]8− and the rare earth cations (Ln = NdIII, EuIII, TbIII), [(CH3)4N]2.5H7.5[Eu(GeW11O39)(H2O)2]2 · 4.5H2O (1), [(CH3)4N]2H8 [Tb(GeW11O39)(H2O)2]2 · 2.5H2O (2) and [Nd0.5(H2O)2]H0.5[Nd2(GeW11O39) (DMSO)2(H2O)8] · 5.5H2O (3), have been synthesized and characterized by elemental analysis, inductively coupled plasmas (ICP) analysis, IR spectroscopy, single-crystal X-ray diffraction. The solid-state structures of compounds 1 and 2 consist of one-dimensional linear wires built of [α-GeW11O39]8− anions connected by Eu3+/Tb3+cations, while in compound 3, the introduction of the organic molecules DMSO (DMSO = dimethyl sulphoxide) leads to a double-parallel chainlike structure constructed by two linear wires {[Nd(1)(GeW11O39)(DMSO)(H2O)2]5−}n linked by Nd3+ coordination cation.